The Rossiter-McLaughlin effect of transiting extrasolar planetary systems

Transcription

1 The Rossiter-McLaughlin effect of transiting extrasolar planetary systems λ = 4 o.4 ± 1 o.4 a transiting planetary system HD209458b Yasushi Suto, Y.Ohta & A.Taruya Department of Physics, The University of Tokyo

2 Extrasolar planet projects at Univ. of Tokyo Search for the planetary atmosphere (HD209458) from the ground observation with Subaru HDS the most stringent upper limits from ground ~0.1% Winn et al. PASJ 56(2004) 655 (astro-ph/ ) Narita et al. PASJ 57(2005) 471 (astro-ph/ ) Constraining the stellar spin and the planetary orbital axes from the Rossiter-McLaughlin effect New analytic formulae (Ohta, Taruya & Suto 2005, 2005, ApJ,, 622, 1118) First detection (Winn et al ApJ in press, astro-ph/ ) Search for rings around extrasolar planets (Ohta et al. 2005) Search for reflected light from planets in progress transiting extrasolar planets!

3 Measurement of Spin-Orbit Alignment in an Extrasolar Planetary System Joshua N. Winn (CfA MIT), Robert W. Noyes, Matthew J. Holman, David B. Charbonneau, Yasuhiro Ohta, Atsushi Taruya, Yasushi Suto, Norio Narita, Edwin L. Turner (Univ. of Tokyo), John A. Johnson, Geoffrey W. Marcy, R. Paul Butler, & Steven S. Vogt astro-ph/ (ApJ 2005, in press)

4 Spectroscopic transit signature: the Rossiter-McLaughlin effect Approaching part Shadow of the planet planet star Receding part Mean wavelength shift of line center Time-dependent asymmetry in the stellar Doppler broadened line profile an apparent anomaly of the stellar radial velocity. originally discussed in eclipsing binary systems long time ago Rossiter (1924) McLaughlin (1924)

5 Radial velocity anomaly due to the Rossiter-McLaughlin effect I planet Spin axis of the star Radial velocity anomaly receding Planetary transit approaching time Planetary orbital axis with respect to the stellar spin axis origin of planets and of the angular momentum

6 Radial velocity anomaly due to the Rossiter-McLaughlin effect II stellar spin Spin axis of the star longer planet line center wavelength shorter in-transit time longer line center wavelength Hoshi Navi February 2005 shorter time

7 Previous result of the Rossiter-McLaughlin effect for an extrasolar transit planetary system HD Origin of angular momentum out of transit in transit HD radial velocity data Stellar rotation and planetary orbit Queloz et al. (2000) A&A 359, L13 ELODIE on 193cm telescope

8 Analytic templates for the velocity anomaly due to the Rossiter -McLaughlin effect Limb darkening: B= 1- ε (1-cos θ) First analytic formula using perturbation theory Ohta, Taruya & Suto (astro-ph/ ApJ 2005, 622, 1118)

9 Precision analysis of the Rossiter- McLaughlin effect for HD the precision fitting of HD with the best data available radial velocity data (Keck) optical photometry (HST) infrared photometry (Spitzer) the first detection of the misalignment between stellar spin and the planetary orbital axes by (-4.4( 4.4±1.4)deg more than an order-of-magnitude improvement of the previous error-bar c.f., 7 degree misalignment known for the Solar system confirms the basic picture, but yet anotherλ λ 0 0 problem other than in cosmology!

10 χ HD parameter fit vobs - v model fobs - fmodel = + σ 2 2nd, obs t n= 1 v n= 1 f t σ t + σ 2nd,model 2 12 free parameters data points d.o.f = =489 best-fit : χ 2 /d.o.f=528/489=1.08 for M * =1.06M sun Winn et al. astro-ph/ ApJ 2005, in press

11 radial velocity (Keck) residuals first detection of non-zero λ! velocity anomaly residuals residuals misalignment angle [deg] (projected) stellar spin velocity [km/s] transit photometry (HST) λ = 4 o.4 ± 3σ detection! Winn et al. astro-ph/ ApJ 2005, in press o 1.4

12 Feasibility to constrain TrES-1 system Radial Velocity anomaly ε=0.64 ε=0 (no limb darkening) time Projected misalignment angle [deg] Stellar rotation velocity [m/s] Mock data analysis using the parameters estimated by Alonso et al. (2004) and the analytic templates by Ohta, Taruya and Suto (2005)

13 Detectability of a ring around an extrasolar transiting planetary system using the Rossiter-McLaughlin effect Search for characteristic anomaly due to a planetary ring in photometric and spectroscopic data during transit δv ~ a few m/s δf/f ~ 0.1% Ohta (2005, ph.d. thesis) Ohta, Taruya & Suto (in prep.)

14 Summary: from mere discovery to characterization of extrasolar planets Transiting extrasolar planets! planetary atmospheric signature (Charbonneau et al. 2001; Winn et al. 2004; Narita et al. 2005) spin-orbit misalignment via the Rossiter effect (Winn et al. 2005) ring systems around extrasolar planets (Ohta, Taruya & Suto 2005) terrestrial planets (Kepler mission 2008?) Ultra-precise photometry and spectroscopy are the key!